Stylus or needle for sound-reproducers.



'PATEN'EED AUG. 25, 1903.

V. H. EMERSON. STYLUS 0R NEEDLE FOR SOUND REPRODUGERS.

PATENTED AUG. 25, 1903. V. H. EMERSON. STYLUS 0E NEEDLE FOR SOUNDREPRODUGERS.

are. 736,948

UNITED STATES Patented August 25, 1903.

PATENT OFFICE.

VICTOR EMERSON, OF NEWARK, NEW JERSEY, ASSIGNOR TO AMERICAN GRAPHOPHONECOMPANY, OF WASHINGTON, DISTRICT OF COLUMBIA, A CORPORATION OF WESTVIRGINIA.

STYLUS OR NEEDLE FOR SOUND-REPRODUCERS.

SPECIFICATION forming part of Letters Patent No. 736,948, dated August25, 1903. Application filed June 27,1902 Serial No. 118,431. (No model.)

To all whom it may concern:

Be it known that I, VICTOR H. EMERSON, a resident of Newark, New Jersey,have invented a new and usefullmproved Stylus or Nee- 5 dle forSound-Reproducers, which invention is fully set forth in the followingspecification.

In reproducing sound from flat-disk records, in which the sound-wavesare represented by I lateral undulations in a groove of even depthformed in a flat disk of rubber composition or similar hard substance, apointed stylusneedle' composed entirely of a hard metal, such as steel,has heretofore been employed 1 5 to track the record and transmitvibrations to the diaphragm. This pointed stylus or needle is removablysecured in the end of a stylus-arm, which communicates the vibrations tothe diaphragm by a lever-like action.

Although the fine point of the stylus or needle is at first sufficientlysharp to engage in the groove and between the side walls thereof, saidpoint rapidly wears away until a part of the conical or tapered point isreached which is of greater diameter than the width of the groove. Theresult is that shoulders are formed which rest and bear upon the upperflat face of the record contiguous to the groove. As is well known anobjectionable 3o sharp grinding, grating, gritting, or scraping noiseaccompanies the sound reproduced from records of the type above referredto, due to the hard metal of the stylus or point bearing against andriding over the surface of the 3 5 hard substance composing therecord-disk. This noise, which is not so objectionable when thereproduction is commenced with a fresh fin ely-pointed stylus orneedle,becomes louder and more objectionable as the point 0 is rapidly wornaway and the shoulders above referred to formed thereon. Effort has beenmade to minimize this objectionable noise by frequent changes of thestylus or needle; but this is-an unsatisfactory expedient, being notonly tedious, but ineffectual, the sharp point of the stylus being verymaterially worn away before the reproduction of a single record has beencompleted. It is impracticable to reduce the stylus or needle to auniform diameter approximating the width of he groove, because it wouldnot then have sufficient rigidity to properly transmit vibrations fromthe record-groove to the diaphragm.

The object of my present invention is to overcome or at least tominimize the objectionable noise above referred to, at the same timeavoiding the necessity of frequent. changes of the stylus or needle.

To that end the invention comprises a stylus or needle having a hardcore which is supported by, surrounded by, incased, or embedded in asupport, body, or covering of softer material. The core, at least at itsend which engages the record-groove, is of a uniform diameterapproximating the width of the record-groove and is preferably made ofhard steel, though other suitable metal or material may be employed.Fine piano-wire has given good practical results. The sup-= port, body,or covering, which is of sufficient thickness ordimensions to impart tothe stylus the required rigidity, is made of a softer metal or materialthan the core, so that it will be readily worn away by contact with therecord disk or tablet without producing objectionable noise. An alloycomposed of equal parts of bismuth and lead has been found to give goodresults.

The invention will be more fully understood by reference to theaccompanying draw ings, wherein- Figure 1 is a perspective view showingpart of a record-disk, a reproducer, and associated part-s. Fig. 2 isalongitudinal sectional view 85 through a stylus or needle embodying myinvention. Fig. 3 is a transverse section on line 3 3 of Fig. 2. Fig. 4is a sectional tlBW showing my improved stylus in engagement with arecord-groove. Figs. 5 to 10, inclusive, are views in section andelevation, illustrating other forms in which the invention may beembodied; and Figs. 11 and 12 are views showing a stylus or needle suchas heretofore used in engagement with a rec- 5 ord-groove. Figs. 2, 3,4., 11, and 12 are drawn on a much-enlarged scale, the ordinarydimensions of the sound-groove shown in several of the figures beingabout five onethousandths of an inch in width by two rco groove.

one-thousandths of an inch in depth. Figs. 5 to 10 are also enlargedviews,.but on a smaller scale.

Referring to Fig. 1, A is a reproducer mounted on the outer end of arm13, which is supported at its other end (not shown) on a universaljoint. 0 is a portion of the horn leading into the reproducer. D is thestylusarm of the reproducer, and E is the stylus or needle removablysecured in the outer end of the stylus-arm by a set-screw e. The stylusor needle engages and tracks the grooves in the sound-record F, saidgrooves having lateral undulations corresponding to sound-waves.

In Fig. 11, F is the point of the ordinary pointed steel stylus nowcommonly used, showing its condition when the operation of reproductionbegins. Fig. 12 is a similar view showing the condition of the pointafter it has been in operation for a short time. The point has Wornaway, forming shoulders ff at opposite sides thereof. bear upon theupper flat face of the recorddisk contiguous to the groove,therebygreatly increasing the objectionable sharp scratching, grating, orgritting noise, as above explained.

As shown in Figs. 2, 3, and 4, my improved stylus comprises a core g,preferably of hardsteel wire (such as piano-wire) of a uniform diameterapproximating the width (ordinarily five one-thousandths of an inch) ofthe record-groove, so that no matter how much the end of the core isworn away it will continue to engage between the side walls of the h isa support of softer material, preferably an alloy of equal parts ofbismuth and lead, surrounding the core and imparting to the stylus orneedle the required ri gidity. The covering may be applied to the coreeither by dipping it into the alloy while the latter is in a liquidmolten state or by molding. As shown in Figs. 2, 3, and 4, the supportor covering is elliptical in cross-section, the greatest diameterthereof being preferably disposed transversely to the groove. Thesefigures also show the lower end of the covering tapered to the lower endof the core, so that the latter will readily'en gage the groove at thebeginning of the operation. As will be readily understood, as the end ofthe core is worn ed the support or covering of softer material will alsobe readily worn away, as indicated, for example, in Fig. 4:, thecharacter of the covering being such that no appreciable sound willresult from the wear thereon. The stylus or needle thus constructed canbe repeatedly used. In fact, it can be used as long as a sufficientlength thereof projects from the stylus-arm.

In Figs. 5 and 6 the covering iis cylindical and of uniform diameterthroughout.

It is not necessary that the core be embedded in the center of or beentirely surrounded by the support. Figs. 7 and 8 show the core membedded in the support at the pe- These shoulders riphery of thelatter, while Figs. 9 and 10 show core 0 soldered to the peripheralsurface of the support 10.

As will be apparent, modifications may be made within wide limitswithout departing from the invention.

The term core as used in the specification and claims is intended todesignate the hard part of the needle irrespective of whether it issurrounded by and embedded in the softer support, body, or covering ormerely secured to the support in such manner as not to be surroundedthereby.

What I claim is- 1. A stylus or needle for use in sound-reproducinginstruments composed of a hard core and a support or body of softermaterial extending along and secured to the core.

2. A stylus or needle for use in sound-reproducing instruments composedof a hard-wire core and a body or support of softer material extendingalong and secured to the core.

3. A stylus or needle for use in sound-reproducing instruments composedof a core of hard metal and a body or support of softer metal extendingalong and secured to the core.

4. A stylus or needle for use in sound-reproducing instruments composedof a hard core and a support or body of softer material extending alongand in which the core is embedded.

5. A stylus or needle for use in sound-reproducing instruments composedof a hard-metal core and a support or body of softer metal extendingalong and in which the core is embedded.

6. A stylus or needle for use in sound-reproducing instruments composedof ahard core and a support or covering of softer material extendingalong and surrounding the core.

7 A stylus or needle for use in sound-reproducing instruments composedof ahard-metal core and a support or covering of softer metal extendingalong and surrounding the core.

8. A stylus or needle for use in sound-reprod'ucinginstruments composedof a hard-metal core and a support of softer metal containing leadextending along and secured to the core.

- 9. A stylus or needle for use in sound-reproducing instrumentscomposed of a hard-metal core and a support or body of bism nth-leadalloy extending along and secured to the core.

10. Astylus or needle for use in reproducing sound from a groovecontaining a record thereof, comprising a hard core of a thicknessapproximating the width of the groove, and a support of softer materialsecured to the core.

11. A stylus or needle for use in reproducing sound from a groovecontaining a record thereof, comprising a hard core of a thicknessapproximating the width of the groove and a support of softer materialin which the core is embedded.

12. A stylus or needle for use in reproducing sound from a groovecontaining a record thereof, comprising a hard core of a thicknessapproximating the width of the groove and a support of softer materialsurrounding the core.

13. A stylus or needle for use in reproducing sound from a groovecontaining a record thereof, comprising a hard-metal core of a thicknessapproximating the width of the groove and a support of softer materialfor thereof comprising a hard-steel core of a thickness approximatingthe width of the record-groove surrounded by a covering of softer metal.

17. A stylus or needle for use in reproducing sound from a groovecontaining a record thereof comprising a hard-steel core of a thicknessapproximating the width of the record-groove surrounded by a covering ofbismuth-lead alloy.

18. The combination with a record-surface having a, groove thereincontaining a record of sound, of a reproducer stylus or needle composedof a hard core adapted to engage in the groove and a support of softermaterial for the core adapted to bear upon the surface of the recordadjacent to the groove.

19. The combination with a record-surface having a groove thereincontaining a record of sound, of a reproducer stylus or needle composedof a hard core adapted to engage in the groove and a support of softermaterial for the core adapted to bear upon the surface of the record atopposite sides of the groove.

20. A stylus or needle for use in reproducing sound from a groovecontaining a record thereof, comprising a hard-metal wire core of adiameter approximately the width of the VICTOR H. EMERSON.

Witnesses:

ELISHA K. CAMP, O..A. L. MASSIE.

